The present invention relates to a new and improved method and apparatus for use in applying powder to workpieces and, more specifically, to an improved nozzle assembly and method which may be used in such an apparatus.
A known apparatus for applying powder to workpieces is disclosed in U.S. Pat. No. 4,987,001 issued Jan. 22, 1991 and entitled "Method and Apparatus for Coating the Interior Surface of Hollow, Tubular Articles". This known apparatus includes a pump which is operable to produce a pulsed flow of air with powder entrained therein. The powder flows from the pump through a charging apparatus which electrostatically charges the powder in the pulses of air. A nozzle assembly directs the pulses of air with electrostatically charged powder therein toward a workpiece.
During the use of apparatus similar to the apparatus disclosed in U.S. Pat. No. 4,987,001, powder may tend to build up within the nozzle assembly which directs the flow of air and powder toward a workpiece. The build up of powder in the nozzle assembly may tend to interfere with the flow of air and powder through the nozzle assembly. In addition, the build up of powder in the nozzle assembly may result in an uneven distribution of powder on at least some workpieces and the application of powder to at least some workpieces in a pattern other than a desired pattern.